This invention relates to an indoor type skiing ground having a ski slope inside a building, a method for controlling the indoor type skiing ground, and a controller for the indoor type skiing ground.
With the progress and diversification of the leisure industry, a demand is growing that skiing be enjoyable in a comfortable environment without influences from natural conditions. To satisfy this demand, indoor type skiing grounds are constructed. This type of skiing ground is created in urban areas and their suburbs, but is also provided in outdoor skiing grounds so that skiing can be enjoyed even in bad weather.
FIG. 27 is a schematic side view showing the inside of a building of a conventional indoor type skiing ground. FIG. 28 is a schematic front view showing the inside of the building of the conventional indoor type skiing ground.
In a conventional indoor type skiing ground, as shown in FIGS. 27 and 28, a slope 002 is formed inside a building 001, and artificial snow 003 is deposited to a predetermined thickness on the slope 002 to form a ski slope 004. Near the ceiling of the building 001, an air compression pipe 005 is mounted, and an air compressor 006 provided outside the building 001 is connected to the air compression pipe 005. Along the air compression pipe 005, a water feed pipe 007 is laid, and a water feeder 008 provided outside the building 001 is connected to the water feed pipe 007. Between the air compression pipe 005 and the water feed pipe 007 arranged in parallel, a plurality of jet nozzles 009 are mounted which are shared by the air compression pipe 005 and the water feed pipe 007. A side wall of the building 001 is pierced by one end portion of a cold air supply pipe 010 which blows cold air into the building 001, and one end portion of an air discharge pipe 011 which discharges air from inside the building 001. The one end portions are open to the interior of the building 001. The other end portions of the cold air supply pipe 010 and the air discharge pipe 011 are connected to an air cooler 012.
Thus, cold air of about -10 to -15.degree. C. is fed from the air cooler 012, and blown into the building 001 through the cold air supply pipe 010. Simultaneously, compressed air is supplied by the air compressor 006 to the air compression pipe 005, while water is supplied by the water feeder 008 to the water feed pipe 007. The compressed air and water are jetted through the jet nozzles 009. The resulting water jets are heat-exchanged with cooled air, and turned into artificial snow 003, which falls on the slope 002. When this procedure is continued for a certain period of time, snow piles up on the slope 002 to form a ski slope 004.
After the ski slope 004 having a certain-thickness layer of artificial snow 003 is formed on the slope 002, the supply of compressed air and water to the jet nozzles 009 is cut off to stop the formation and fall of artificial snow. Thus, skiers can enjoy skiing on the ski slope 004 blanketed with a satisfactory thickness of artificial snow in the state of snow not falling.
The cold air supply pipe 010 always blows cold air into the building 001. Even when artificial snow is not falling, this cooling air cools the entire interior of the building 001 to about -5 to -10.degree. C., and thus can maintain the artificial snow 003 from compressed air and water in a good condition. To maintain artificial snow 003 of a high quality, the temperature of the surface of the artificial snow 003 needs to be held at a predetermined value (e.g., 2.degree. C.) or less. To hold the snow surface temperature at 2.degree. C. or lower, cold air of about -5 to -10.degree. C. is continuously blown off, for example, to cool all the interior of the building 001.
With the conventional indoor type skiing ground, as described above, cold air of about -10 to -15.degree. C. was fed into the building 001 by the air cooler 012. Simultaneously, compressed air and water were supplied from the air compressor 006 and water feeder 008, and jetted through the jet nozzles 009. Thus, the resulting water sprays were formed into artificial snow 003, which accumulated on the slope 002 to form the ski slope 004. To main the quality of the artificial snow 003 of the ski slope 004 at a high level, cold air was supplied throughout the inside of the building 001 so that the inside temperature was lowered to about -5 to -10.degree. C.
To produce artificial snow 003 inside the building 001 and pile it up on the slope 002, all the interior of the building 001 has to be cooled. The air cooler 012 for supplying cold air into the building 001 is required to have a high capacity. Thus, this apparatus necessarily grows in size and its energy cost increases. It may be recommendable to bring the cold air supply pipe 010 to a lower height close to the snow surface, thereby cooling the snow surface principally. For a wide ski slope 004, however, cold air fails to reach its central area, which does not become cold at a suitable temperature. Besides, the areas near the outlet of the cold air supply pipe 110 are cooled considerably strongly. In these areas, snow that begins to melt becomes granulated, or a frozen ski slope is formed.
To maintain the ski slope 004 of a satisfactory quality, the operator's experience and sense were relied on to constantly supply cooling air to the inside of the building 001, thereby cooling it to about -5 to -10.degree. C. However, the inside of the building 001 tended to be cooled excessively.
With the conventional indoor type skiing ground, as noted above, much labor was required, and the running cost became high, in order to maintain the snow quality of the ski slope 004 at a satisfactory level.
Furthermore, the entire interior of the building 001 was cooled with cold air from the cold air supply pipe 010 provided above. Hence, air at an upper position apart from the surface of the artificial snow 003 (e.g., the position of a skier's face) was at a subzero temperature, which made it difficult for skiers or workers to stay there for long periods of time. Skiers, in particular, did not feel entirely comfortable, and were unable to enjoy skiing in light dress.
To maintain the artificial snow 003 of the ski slope 004 in good condition, cooling air is supplied through the cold air supply pipe 010 to the entire interior of the building 001, which is thereby cooled to about -5 to -10.degree. C. However, the artificial snow 003 of the ski slope 004 receives heat from lighting, radiant heat from the ceiling and side wall, or heat from glides of skis. Thus, the quality of snow in the ski slope 004 is gradually deteriorating.
When the quality of the artificial snow 003 of the ski slope 004 deteriorated, it was customary practice to scrape off and discharge the artificial snow 003 on the surface of the ski slope 004 at predetermined time intervals, sprinkle fresh artificial snow 003 over the entire area of the ski slope 004, and smooth it mechanically.
However, artificial snow 003 does not deteriorate in some places of the ski slope 004, so that there is no need to sprinkle fresh artificial snow 003 throughout the surface of the ski slope 004. Sprinkling fresh artificial snow 003 throughout the surface of the ski slope 004 requires that the entire area of the ski slope 004 be smoothed mechanically, thus making the operation extensive.
When the deteriorated artificial snow 003 of the ski slope 004 is to be scraped off and discharged, the ski slope 004 must be shut off to stop ski glides before the scraping operation is performed. Thus, the duration of use of the ski slope 004 is restricted. If the task of scraping off and discharging the artificial snow 003 of the ski slope 004 is to be carried out during the service hours of the ski slope 004, this task becomes tiresome. Furthermore, a dedicated machine is needed for scraping off a predetermined thickness of artificial snow 003 from the ski slope 004, and another dedicated machine becomes necessary for discharging the scraped snow.
When the set value of the inside temperature of the building 001 is increased, and the artificial snow 003 is renewed while being thawed, thawing occurs in the entire surface of the ski slope 004. The resulting meltwater cannot be drained appropriately, and an increased amount of dwelling water converts the artificial snow into sleet, thereby making ski glides impossible.
The present invention aims at solving the foregoing problems. A first object of the invention is to maintain a satisfactory quality of artificial snow and enable skiers to enjoy skiing in a relatively light dress, without performing excessive cooling.
A second object of the invention is to maintain the snow quality of a ski slope constantly at a satisfactory level, while reducing the energy cost, with the use of a simple and inexpensive structure.
A third object of the invention is to maintain the snow quality of a ski slope constantly at a satisfactory level, while decreasing the amount of snow thawed, with the use of a simple and inexpensive structure, and increase the accuracy of control for maintaining a good quality of snow to curtail energy consumption.